A tap changer may be connected to a transformer to produce an output voltage that is self-regulated (i.e., substantially constant at a predetermined target level) despite fluctuations that may occur in the input voltage and/or load. An AC voltage regulator for industrial use may typically comprise a tap changer having a number of spaced-apart output terminals and performs its regulatory function by adjusting the tap position (i.e., tapping the output terminals at a selectable position) so that, for a given input voltage, the output is taken from whichever tap yields an output voltage closest to the target level.
In known tap changer circuitry, movable contacts may operate at relatively high voltages (e.g., thousands of volts) and thus such contacts may be subject to electrical arcing during tap changes. Although the movable contacts are rated to withstand electrical arcing, in practice the repeated exposure to electrical arcing may lead to eventual wear and tear (e.g., burning and/or electrical erosion) of the movable contacts of the tap changer, which may require relatively frequent maintenance to address such wear and tear. Additionally, the electrical arcing may lead to other operational drawbacks, such as the formation of combustible gases and/or debris in an insulating transformer oil. In view of the foregoing considerations, it is desirable to provide an improved tap changer circuitry that reliably and in a cost-effective manner avoids or reduces the drawbacks discussed above